Here in western New York, the shade-loving hosta plant is so common that almost every garden has at least one, and many have hundreds. Slugs, deer and other garden creatures find them too tempting to resist, it’s true, but aside from that minor detail they’ve been relatively carefree plants, until now.

Now hosta is facing an even scarier foe than Bambi: Hosta Virus X.

Virus X is a member of the potexvirus—or mosaic—group. It may cause the leaves to twist or pucker, but its most common symptom is mottling and “irregular green colors that might be mistaken for variegation except for that this is kind of ugly,” said Brian Eshenaur, Horticulture Program Leader with Monroe County’s Cornell Cooperative Extension.

The fact that the manifestation of the virus can look so much like healthy variegation is largely to blame for its spread in the marketplace. For example, the variety ‘Breakdance’ is 100% infected. That’s because it’s actually not a “variety” at all. What at first looked like a cool new sport (an offshoot of the parent that is different in some way) turned out to be just an infected plant, but not before it was introduced into the trade, where it came in contact with, and infected, whole batches of healthy plants. The same is true of ‘Eternal Father’ and ‘Leopard Frog’. Do not buy these plants.

Be wary of ‘Sum and Substance,’ ‘Striptease’ and ‘Gold Standard’, popular (and valid) varieties that are very common hosts, and any hosta with gold leaf coloring, a common trait of easily-infected plants.

Eshenaur said that a local crisis was at least temporarily averted this spring when Penfield gardener Donna Eggleston noticed infected plants at a large home store and informed state authorities. “Within a week the whole lot was removed from commerce. It’s a good thing,” he added.

There’s no known cure for the virus, and it’s systemic, which means that it affects the whole plant—you can’t just cut off an infected part, you have to dispose of the whole plant (not in the compost pile).

If you see Virus X in a garden center, alert the management. If you see it in your garden, get it out—fast. The virus spreads via the plants’ sap, so it’s you should disinfect any tools you use on one hosta before moving on to the next one, even if you don’t see any symptoms (the disease can take years to show itself). It can only survive in living tissue, so once you have removed an infected plant, the virus will be gone too. But be careful about replanting hosta in the same spot—if you do so immediately, the new plant may come in contact with infected pieces of root in the soil. It’s a good idea to wait until you are sure these have had a chance to rot away.

For more information and pictures to help in identification, visit
http://www.rochestergardening.com/hvx/index.html
http://www.hostalibrary.org/firstlook/HVX.htm
http://www.ipm.msu.edu/CAT05_land/L05-13-05hosta.htm

Copyright 2005, Jane Milliman